Worked in London under Sir William Ramsay and at McGill University (discovering radioactinium) under Ernest Rutherford. In Germany with Fritz Strassmann in 1938 he discovered fission of uranium and thorium, the phenomenon of which was then explained by Lise Meitner and Otto Robert Frisch. While he discovered fission, he was not a part of Germany's atomic bomb program. For his discovery he was awarded the 1944 Nobel Prize for Chemistry, but was unable to collect his award due to his being held prisoner in Britain.